Build a Basic CRUD App with Angular and Node — SitePoint

In recent years, single page applications (SPAs) have become more and more popular. A SPA is a website that consists of just one page. That lone page acts as a container for a JavaScript application. The JavaScript is responsible for obtaining the content and rendering it within the container. The content is typically obtained from a web service and RESTful APIs have become the go-to choice in many situations. The part of the application making up the SPA is commonly known as the client or front-end, while the part responsible for the REST API is known as the server or back-end. In this tutorial, you will be developing a simple Angular single page app with a REST backend, based on Node and Express.

You’ll be using Angular as it follows the MVC pattern and cleanly separates the View from the Models. It is straightforward to create HTML templates that are dynamically filled with data and automatically updated whenever the data changes. I have come to love this framework because it is very powerful, has a huge community and excellent documentation.

For the server, you will be using Node with Express. Express is a framework that makes it easy to create REST APIs by allowing to define code that runs for different requests on the server. Additional services can be plugged in globally, or depending on the request. There are a number of frameworks that build on top of Express and automate the task of turning your database models into an API. This tutorial will not make use of any of these in order to keep this focused.

Angular encourages the use of TypeScript. TypeScript adds typing information to JavaScript and, in my opinion, is the future of developing large scale applications in JavaScript. For this reason, you will be developing both client and server using TypeScript.

Here are the libraries you’ll be using for the client and the server:

Angular: The framework used to build the client application

Okta for Authorisation: A plugin that manages single sign-on authorization using Okta, both on the client and the server

Let’s get started by implementing a basic client using Angular. The goal is to develop a product catalog which lets you manage products, their prices, and their stock levels. At the end of this section, you will have a simple application consisting of a top bar and two views, Home and Products. The Products view will not yet have any content and nothing will be password protected. This will be covered in the following sections.

To start you will need to install Angular. I will assume that you already have Node installed on your system and you can use the npm command. Type the following command into a terminal.

Depending on your system, you might need to run this command using sudo because it will install the package globally. The angular-cli package provides the ng command that is used to manage Angular applications. Once installed go to a directory of your choice and create your first Angular application using the following command.

ng new MyAngularClient

Using Angular 7, this will prompt you with two queries. The first asks you if you want to include routing. Answer yes to this. The second query relates to the type of style sheets you want to use. Leave this at the default CSS.

ng new will create a new directory called MyAngularClient and populate it with an application skeleton. Let’s take a bit of time to look at some of the files that the previous command created. At the src directory of the app, you will find a file index.html that is the main page of the application. It doesn’t contain much and simply plays the role of a container. You will also see a style.css file. This contains the global style sheet that is applied throughout the application. If you browse through the folders you might notice a directory src/app containing five files.

These files define the main application component that will be inserted into the index.html. Here is a short description of each of the files:

app.component.css file contains the style sheets of the main app component. Styles can be defined locally for each component

app.component.html contains the HTML template of the component

app.component.ts file contains the code controlling the view

app.module.ts defines which modules your app will use

app-routing.module.ts is set up to define the routes for your application

app.component.spec.ts contains a skeleton for unit testing the app component

I will not be covering testing in this tutorial, but in real life applications, you should make use of this feature. Before you can get started, you will need to install a few more packages. These will help you to quickly create a nicely designed responsive layout. Navigate to the base directory of the client, MyAngularClient, and type the following command.

The @angular/material and @angular/cdk libraries provide components based on Google’s Material Design, @angular/animations is used to provide smooth transitions, and @angular/flex-layout gives you the tools to make your design responsive.

Next, create the HTML template for the app component. Open src/app/app.component.html and replace the content with the following.

This is the controller for the app component. You can see that it contains a property called isAuthenticated together with two methods login and logout. At the moment these don’t do anything. They will be implemented in the next section which covers user authentication with Okta. Now define all the modules you will be using. Replace the contents of app.module.ts with the code below:

Notice all the material design modules. The @angular/material library requires you to import a module for each type of component you wish to use in your app. Starting with Angular 7, the default application skeleton contains a separate file called app-routing.module.ts. Edit this to declare the following routes.

This defines two routes corresponding to the root path and to the products path. It also attaches the HomeComponent and the ProductsComponent to these routes. Create these components now. In the base directory of the Angular client, type the following commands.

ng generate component Products
ng generate component Home

This creates html, css, ts, and spec.ts files for each component. It also updates app.module.ts to declare the new components. Open up home.component.html in the src/app/home directory and paste the following content.

Leave the ProductsComponent empty for now. This will be implemented once you have created the back-end REST server and are able to fill it with some data. To make everything look beautiful only two little tasks remain. Copy the following styles into src/style.css

You are now ready to fire up the Angular server and see what you have achieved so far. In the base directory of the client app, type the following command.

ng serve

Then open your browser and navigate to http://localhost:4200.

Add Authentication to Your Node + Angular App

If you have ever developed web applications from scratch you will know how much work is involved just to allow users to register, verify, log on and log out of your application. Using Okta this process can be greatly simplified. To start off, you will need a developer account with Okta.

In your browser, navigate to developer.okta.com and click on Create Free Account and enter your details.

Once you are done you will be taken to your developer dashboard. Click on the Add Application button to create a new application.

Start by creating a new single page application. Choose Single Page App and click Next.

On the next page, you will need to edit the default settings. Make sure that the port number is 4200. This is the default port for Angular applications.

That’s it. You should now see a Client ID which you will need to paste into your TypeScript code.

To implement authentication into the client, install the Okta library for Angular.

Here yourOktaDomain should be replaced by the development domain you see in your browser when you navigate to your Okta dashboard. YourClientId has to be replaced by the client ID that you obtained when registering your application. The code above makes the Okta Authentication Module available in your application. Use it in app.component.ts, and import the service.

Now, any changes in the authentication status will be reflected in the isAuthenticated property. You will still need to initialize it when the component is loaded. Create a ngOnInit method and add implements OnInit to your class definition

That’s all there is to it. Now, when a user tries to access the Products view, they will be redirected to the Okta login page. Once logged on, the user will be redirected back to the Products view.

Implement a Node REST API

The next step is to implement a server based on Node and Express that will store product information. This will use a number of smaller libraries to make your life easier. To develop in TypeScript, you’ll need typescript and tsc. For the database abstraction layer, you will be using TypeORM. This is a convenient library that injects behavior into TypeScript classes and turns them into database models. Create a new directory to contain your server application, then run the following command in it.

The first step in creating the server is to create a database model for the product. Using TypeORM this is straightforward. Create a subdirectory src and inside that create a file model.ts. Paste the following content.

The TypeORM annotations turn the class definition into a database model. I love the TypeORM project because of its ease of use and the wide variety of SQL and NoSQL database connectors that are supported. I suggest that you check out the documentation at https://github.com/typeorm/typeorm.

You will also need to get access to a repository of product. Also in the model.ts file add the following.

Just as in the client application yourOktaDomain should be replaced by the development domain and YourClientId has to be replaced by your application client ID. The oktaJwtVerifier instance takes a JWT token and authenticates it. If successful, the user id and email will be stored in req.user. Otherwise, the server will respond with a 401 status code. The final piece to complete the server is the main entry point that actually starts the server and registers the middleware you have defined so far. Create a file server.ts with the following content.

Finish Your Angular Client

Now that the server is complete let’s finish off the client. The first step is to create a class that contains the Product data. This class is similar to the Product class in the server application but without the TypeORM annotations. It will be contained in a file called product.ts.

The ProductsService contains one public method for each route of the REST API. The HTTP request is encapsulated in a separate method. Note how the request always contains a Bearer token obtained from the OktaAuthService. This is the token used by the server to authenticate the user.

Now the ProductsComponent can be implemented. The following code will do the trick.

The layout, in products.component.html, showing the product consists of two parts. The first part uses a mat-table component to display a list of products. The second part shows a form in which the user can edit a new or existing product.

When all is done, you can start the client and the server up and test your application. Just to repeat, in the directory containing the server, run:

node dist/server.js

And in the client directory, run:

ng serve

Your application should look somewhat like the following

Learn More About Angular, Node, and Express

In this tutorial, I have guided you through the development of a single page web application using Angular and Node. Using just a few lines of code you were able to implement user authentication for the client and the server. Angular makes use of TypeScript which is a superset of the JavaScript language and adds type information. TypeScript makes for more stable code and that is why I decided to also implement the Node/Express server using this language. If you are not yet familiar with TypeScript, check out this great introduction by Todd Motto. He also has some good articles on Angular.